As its name suggests, a linear regulator is a system used to maintain a steady voltage. The resistance of the regulator varies in accordance with the load, resulting in a constant voltage output. All linear regulators require an input voltage at least some minimum amount higher than the desired output voltage. That minimum amount is called the dropout voltage. A low-dropout, or LDO, regulator is a DC linear regulator which can regulate the output voltage even when the supply voltage is very close to the output voltage. Linear regulators are a great choice for powering devices that require stable voltage rails (like processors) or applications where the difference between the input voltage and output voltage is small. They are a simple and cheap solution, but linear regulators are normally inefficient because the difference between the input voltage and regulated output voltage is continually dissipated as heat. A switching regulator is a voltage regulator that uses a switching element to transform the incoming power supply into a pulsed voltage, which is then smoothed using capacitors, inductors, and other elements. Power is supplied from the input to the output by turning on a switch (MOSFET) until the desired voltage is reached. Once the output voltage reaches the predetermined value, the switch element is turned off and no input power is consumed. Repeating this operation at high speeds makes it possible to supply voltage efficiently and with less heat generation. There are mainly two types: boost and buck. Boost output will be higher than the input; therefore its name, as it "boosts" the input voltage. The buck regulator is the opposite, generating a lower voltage from its input. Given the nature and architecture of a switching regulator, they will always have a ripple voltage. First, the designer needs to understand the voltage ripple requirements and limits of the application.